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f2fs: consider fallocated space for SEEK_DATA

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If an amount of data are allocated though fallocate and user writes a couple of
data among the space, f2fs should return the data offset made by user when
SEEK_DATA is requested.

For example, (N: NEW_ADDR by fallocate, X: NEW_ADDR by user)
1) fallocate 0 ~ 10MB
f -> N N N N N N N N N N N N ... N

2) write 4KB at 5MB offset
f -> N N N N N X N N N N N N ... N

3) SEEK_DATA from 0 should return 5MB offset

So, this patch adds a routine to search the first dirty page to handle that.
Then, the SEEK_DATA flow skips NEW_ADDR offsets until any dirty page is found.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This commit is contained in:
Jaegeuk Kim 2014-04-28 18:12:36 +09:00
parent fe369bc8ba
commit 7f7670fe9f
1 changed files with 41 additions and 4 deletions
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45
fs/f2fs/file.c
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@ -19,6 +19,7 @@
#include <linux/compat.h>
#include <linux/uaccess.h>
#include <linux/mount.h>
#include <linux/pagevec.h>
#include "f2fs.h"
#include "node.h"
@ -194,13 +195,48 @@ out:
return ret;
}
static pgoff_t __get_first_dirty_index(struct address_space *mapping,
pgoff_t pgofs, int whence)
{
struct pagevec pvec;
int nr_pages;
if (whence != SEEK_DATA)
return 0;
/* find first dirty page index */
pagevec_init(&pvec, 0);
nr_pages = pagevec_lookup_tag(&pvec, mapping, &pgofs, PAGECACHE_TAG_DIRTY, 1);
pgofs = nr_pages ? pvec.pages[0]->index: LONG_MAX;
pagevec_release(&pvec);
return pgofs;
}
static bool __found_offset(block_t blkaddr, pgoff_t dirty, pgoff_t pgofs,
int whence)
{
switch (whence) {
case SEEK_DATA:
if ((blkaddr == NEW_ADDR && dirty == pgofs) ||
(blkaddr != NEW_ADDR && blkaddr != NULL_ADDR))
return true;
break;
case SEEK_HOLE:
if (blkaddr == NULL_ADDR)
return true;
break;
}
return false;
}
static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file->f_mapping->host;
loff_t maxbytes = inode->i_sb->s_maxbytes;
struct dnode_of_data dn;
pgoff_t pgofs, end_offset;
loff_t data_ofs = offset, isize;
pgoff_t pgofs, end_offset, dirty;
loff_t data_ofs = offset;
loff_t isize;
int err = 0;
mutex_lock(&inode->i_mutex);
@ -218,6 +254,8 @@ static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence)
pgofs = (pgoff_t)(offset >> PAGE_CACHE_SHIFT);
dirty = __get_first_dirty_index(inode->i_mapping, pgofs, whence);
for (; data_ofs < isize; data_ofs = pgofs << PAGE_CACHE_SHIFT) {
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
@ -244,8 +282,7 @@ static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence)
block_t blkaddr;
blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);
if ((whence == SEEK_DATA && blkaddr != NULL_ADDR) ||
(whence == SEEK_HOLE && blkaddr == NULL_ADDR)) {
if (__found_offset(blkaddr, dirty, pgofs, whence)) {
f2fs_put_dnode(&dn);
goto found;
}